The purpose of a firewall is to protect a computer network or device by monitoring and controlling incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and untrusted external networks, such as the internet, to prevent unauthorized access, cyber attacks, and the spread of malicious content. Firewalls filter traffic to allow safe and authorized communications while blocking potentially harmful data, such as viruses, backdoors, denial-of- service attacks, and phishing attempts

. Firewalls can be hardware devices, software programs, or a combination of both, and they serve as the first line of defense in network security. They help secure private data, prevent unauthorized users from accessing sensitive areas of the network, and can also enforce policies like restricting access to inappropriate websites or managing bandwidth usage. Advanced firewalls, often called next-generation firewalls, include features like deep packet inspection, application control, intrusion prevention, and malware defense

. While firewalls are critical for network security, they do not protect against all threats, such as malware introduced through email links or insider attacks, so additional security measures like antivirus software are often necessary

. Overall, the primary purpose of a firewall is to secure networks by allowing legitimate traffic and blocking malicious or unauthorized traffic to reduce the risk of cyber threats